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AT25F4096

2454G–SFLSH–5/06

Functional

Description

The AT25F4096 is designed to interface directly with the synchronous serial peripheral

interface (SPI) of the 6800 type series of microcontrollers.

The AT25F4096 utilizes an 8-bit instruction register. The list of instructions and their

operation codes are contained in Table 5. All instructions, addresses, and data are

transferred with the MSB first and start with a high-to-low transition.

Write is defined as program and/or erase in this specification. The following commands,

Program, Sector Erase, Chip Erase, and WRSR are write instructions for AT25F4096.

WRITE ENABLE (WREN): The device will power up in the write disable state when V

CC

is applied. All write instructions must therefore be preceded by the WREN instruction.

WRITE DISABLE (WRDI): To protect the device against inadvertent writes, the WRDI

instruction disables all write commands. The WRDI instruction is independent of the sta-

tus of the WP pin.

READ STATUS REGISTER (RDSR): The RDSR instruction provides access to the sta-

tus register. The Ready/Busy and Write Enable status of the device can be determined

by the RDSR instruction. Similarly, the block write protection bits indicate the extent of

protection employed. These bits are set by using the WRSR instruction. During internal

write cycles, all other commands will be ignored except the RDSR instruction.

Table 5. Instruction Set for the AT25F4096

Instruction Name

Instruction

Format

Operation

WREN

0000 X110

Set Write Enable Latch

WRDI

0000 X100

Reset Write Enable Latch

RDSR

0000 X101

Read Status Register

WRSR

0000 X001

Write Status Register

READ

0000 X011

Read Data from Memory Array

PROGRAM

0000 X010

Program Data Into Memory Array

SECTOR ERASE

0101 X010

Erase One Sector in Memory Array

CHIP ERASE

0110 X010

Erase All Sectors in Memory Array

RDID

0001 X101

Read Manufacturer and Product ID

Table 6. Status Register Format

Bit 7

Bit 6

Bit 5

Bit 4

Bit 3

Bit 2

Bit 1

Bit 0

WPEN

X

X

BP2

BP1

BP0

WEN

RDY